Many industries utilize hot melt adhesives and sealant materials for a wide range of applications. Hot melt materials are typically solid thermoplastics that become fluid at elevated temperatures and re-solidify upon cooling to form a bond or create a seal. Hot melt materials may be useful for bonding a wide variety of substrates, including wood, metal, foam, plastic, paper, textiles, and more. These hot melt materials are stored and transported in solid form and must be melted before they can be used in their final application. Hot melt systems generally include a hopper or tank for receiving solid hot melt material and a heating element to melt the material. After melting, the hot melt fluid is selectively dispensed via a handgun, for example.
Hot melt systems perform best when their melt tanks are kept sufficiently full. In some systems, when a tank empties, it may take an hour or more to resume full production upon refilling, which results in lost productivity. Some known systems use a capacitive level detection sensor to monitor the level of hot melt adhesive in the tank to prevent the tank from emptying.